Abstract: The invention relates to an optical isolator comprising a polarizer adapted to polarize a beam of incident light to form a beam of polarized light, an analyzer adapted to transmit said beam of polarized light and to polarize back-reflected light, a magneto-optical element disposed between the polarizer and the analyzer, which magneto-optical element rotates the polarization direction of said beam of polarized light, and a magnet generating a magnetic field penetrating said magneto-optical element. It is an object of the invention to provide a temperature-compensated optical isolator that achieves a high degree of isolation at a minimum insertion loss over a given temperature range, without any need of manual tuning. The invention proposes to make provision for an automatic actuator mechanically connected to said magneto-optical element to move said magneto-optical element relative to said magnet in response to a temperature variation or in response to a variation of the wavelength of the incident light.